Inverse function

How can you find the inverse of by restricted the domain?

I looked at this and expected to end up with a square root of something, so that you could restrict the domain to only include positive or negative values, but then I tried to solve , and couldn't. Can anyone help?

I looked at this and expected to end up with a square root of something, so that you could restrict the domain to only include positive or negative values, but then I tried to solve , and couldn't. Can anyone help?

I don't know if it stands for any equation of this type, but it's worth the try.